As a vehicle-mounted electronic control unit (computer) for carrying out, for example, the engine control and transmission control of a vehicle such as an automobile, a system is known in which vehicle-type-specific programs and various forms of data necessary for vehicle control can be rewritten via serial communication, with the use of a rewritable nonvolatile storage means such as EEPROM, the data of which can be rewritten with an external device via a serial communication interface (JP Patent Publication (Kokai) No. 6-33828 A (1994), for example).
Further, a system for operating vehicle-mounted control units is proposed in which a server at an information management center and a communication terminal connected to a vehicle-mounted control unit are able to communicate bidirectionally with one another via a wide area communication network such as a public telephone network. In the system, the vehicle-mounted control unit issues a program transmission request to the information management center. The information management center selects a relevant program from its server and transmits it to the communication terminal. The vehicle-mounted control unit loads the program received by the communication terminal and records the program in a rewritable nonvolatile storage means (JP Patent Publication (Kokai) No. 2002-44742 A, for example).
In the above system for operating vehicle-mounted control units, programs and the like of the vehicle-mounted control unit of a target vehicle can be updated without transporting the vehicle to a dealer for an update. However, since the update is initiated at the intention of the vehicle user, a burden is placed on the vehicle user. Thus, there may be cases in which the vehicle-mounted control unit is not maintained in its optimum state due to user-side problems, for example, such as when the user either forgets to or decides not to update. Additionally, manufacturers and dealers need to inform many users of the need for program modification and update via postcard, e-mail, or the like whenever such need arises.
The present invention has been made in consideration of the above problems. It is an object of the invention to improve the efficiency of updating of programs and data in vehicle-mounted equipment. Specifically, it is an object of the invention to provide an information updating method for a vehicle-mounted control unit, an update information communication system, a vehicle-mounted control unit, and an information management base station unit for providing an updating service whereby the update of programs and data in vehicle-mounted devices can be carried out without placing a burden on vehicle users and without the manufacturers or dealers notifying the users of the need for program modification or update via postcard, e-mail, or the like every time such need arises. In this way, the failure to update the vehicle-mounted control unit due to user-side problems can be completely eliminated and the vehicle-mounted control unit can be always maintained in its optimum state.